script/dom/fetch/
headers.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5use std::cell::Cell;
6use std::str::{self, FromStr};
7
8use dom_struct::dom_struct;
9use http::header::{HeaderMap as HyperHeaders, HeaderName, HeaderValue};
10use js::context::JSContext;
11use js::rust::HandleObject;
12use net_traits::fetch::headers::{
13    extract_mime_type, get_decode_and_split_header_value, get_value_from_header_list,
14    is_forbidden_method,
15};
16use net_traits::request::is_cors_safelisted_request_header;
17use net_traits::trim_http_whitespace;
18use script_bindings::cell::DomRefCell;
19use script_bindings::cformat;
20use script_bindings::reflector::{Reflector, reflect_dom_object_with_proto};
21use style::str::starts_with_ignore_ascii_case;
22
23use crate::dom::bindings::codegen::Bindings::HeadersBinding::{HeadersInit, HeadersMethods};
24use crate::dom::bindings::error::{Error, ErrorResult, Fallible};
25use crate::dom::bindings::iterable::Iterable;
26use crate::dom::bindings::root::DomRoot;
27use crate::dom::bindings::str::{ByteString, is_token};
28use crate::dom::globalscope::GlobalScope;
29
30#[dom_struct]
31pub(crate) struct Headers {
32    reflector_: Reflector,
33    guard: Cell<Guard>,
34    #[no_trace]
35    header_list: DomRefCell<HyperHeaders>,
36}
37
38/// <https://fetch.spec.whatwg.org/#concept-headers-guard>
39#[derive(Clone, Copy, Debug, JSTraceable, MallocSizeOf, PartialEq)]
40pub(crate) enum Guard {
41    Immutable,
42    Request,
43    RequestNoCors,
44    Response,
45    None,
46}
47
48impl Headers {
49    pub(crate) fn new_inherited() -> Headers {
50        Headers {
51            reflector_: Reflector::new(),
52            guard: Cell::new(Guard::None),
53            header_list: DomRefCell::new(HyperHeaders::new()),
54        }
55    }
56
57    pub(crate) fn new(cx: &mut JSContext, global: &GlobalScope) -> DomRoot<Headers> {
58        Self::new_with_proto(cx, global, None)
59    }
60
61    fn new_with_proto(
62        cx: &mut JSContext,
63        global: &GlobalScope,
64        proto: Option<HandleObject>,
65    ) -> DomRoot<Headers> {
66        reflect_dom_object_with_proto(cx, Box::new(Headers::new_inherited()), global, proto)
67    }
68}
69
70impl HeadersMethods<crate::DomTypeHolder> for Headers {
71    /// <https://fetch.spec.whatwg.org/#dom-headers>
72    fn Constructor(
73        cx: &mut JSContext,
74        global: &GlobalScope,
75        proto: Option<HandleObject>,
76        init: Option<HeadersInit>,
77    ) -> Fallible<DomRoot<Headers>> {
78        let dom_headers_new = Headers::new_with_proto(cx, global, proto);
79        dom_headers_new.fill(init.as_ref())?;
80        Ok(dom_headers_new)
81    }
82
83    /// <https://fetch.spec.whatwg.org/#concept-headers-append>
84    fn Append(&self, name: ByteString, value: ByteString) -> ErrorResult {
85        self.append(name, &value)
86    }
87
88    /// <https://fetch.spec.whatwg.org/#dom-headers-delete>
89    fn Delete(&self, name: ByteString) -> ErrorResult {
90        // Step 1 If validating (name, ``) for this returns false, then return.
91        let Some(mut valid_name) = self.validate_name_and_value(name, b"")? else {
92            return Ok(());
93        };
94
95        // Validated tokens are always ASCII.
96        valid_name.make_ascii_lowercase();
97
98        // Step 2 If this’s guard is "request-no-cors", name is not a no-CORS-safelisted request-header name,
99        // and name is not a privileged no-CORS request-header name, then return.
100        if self.guard.get() == Guard::RequestNoCors &&
101            !is_cors_safelisted_request_header(&valid_name, &b"invalid".to_vec())
102        {
103            return Ok(());
104        }
105
106        // 3. If this’s header list does not contain name, then return.
107        // 4. Delete name from this’s header list.
108        self.header_list.borrow_mut().remove(valid_name);
109
110        // 5. If this’s guard is "request-no-cors", then remove privileged no-CORS request-headers from this.
111        if self.guard.get() == Guard::RequestNoCors {
112            self.remove_privileged_no_cors_request_headers();
113        }
114
115        Ok(())
116    }
117
118    /// <https://fetch.spec.whatwg.org/#dom-headers-get>
119    fn Get(&self, name: ByteString) -> Fallible<Option<ByteString>> {
120        // 1. If name is not a header name, then throw a TypeError.
121        let valid_name = validate_name(name)?;
122
123        // 2. Return the result of getting name from this’s header list.
124        Ok(
125            get_value_from_header_list(&valid_name, &self.header_list.borrow())
126                .map(ByteString::new),
127        )
128    }
129
130    /// <https://fetch.spec.whatwg.org/#dom-headers-getsetcookie>
131    fn GetSetCookie(&self) -> Vec<ByteString> {
132        // 1. If this’s header list does not contain `Set-Cookie`, then return « ».
133        // 2. Return the values of all headers in this’s header list whose name is a
134        // byte-case-insensitive match for `Set-Cookie`, in order.
135        self.header_list
136            .borrow()
137            .get_all("set-cookie")
138            .iter()
139            .map(|v| ByteString::new(v.as_bytes().to_vec()))
140            .collect()
141    }
142
143    /// <https://fetch.spec.whatwg.org/#dom-headers-has>
144    fn Has(&self, name: ByteString) -> Fallible<bool> {
145        // 1. If name is not a header name, then throw a TypeError.
146        let valid_name = validate_name(name)?;
147        // 2. Return true if this’s header list contains name; otherwise false.
148        Ok(self.header_list.borrow_mut().get(&valid_name).is_some())
149    }
150
151    /// <https://fetch.spec.whatwg.org/#dom-headers-set>
152    fn Set(&self, name: ByteString, value: ByteString) -> Fallible<()> {
153        // 1. Normalize value
154        let value = trim_http_whitespace(&value);
155
156        // 2. If validating (name, value) for this returns false, then return.
157        let Some(mut valid_name) = self.validate_name_and_value(name, value)? else {
158            return Ok(());
159        };
160        // Validated tokens are always ASCII.
161        valid_name.make_ascii_lowercase();
162
163        // 3. If this’s guard is "request-no-cors" and (name, value) is not a
164        // no-CORS-safelisted request-header, then return.
165        if self.guard.get() == Guard::RequestNoCors &&
166            !is_cors_safelisted_request_header(&valid_name, &value)
167        {
168            return Ok(());
169        }
170
171        // 4. Set (name, value) in this’s header list.
172        // https://fetch.spec.whatwg.org/#concept-header-list-set
173        match (
174            HeaderName::from_str(&valid_name),
175            HeaderValue::from_bytes(value),
176        ) {
177            (Ok(name), Ok(value)) => {
178                self.header_list.borrow_mut().insert(name, value);
179            },
180            _ => {
181                warn!("Could not set header:  \"{valid_name:?}: {value:?}\"");
182            },
183        };
184
185        // 5. If this’s guard is "request-no-cors", then remove privileged no-CORS request-headers from this.
186        if self.guard.get() == Guard::RequestNoCors {
187            self.remove_privileged_no_cors_request_headers();
188        }
189
190        Ok(())
191    }
192}
193
194impl Headers {
195    pub(crate) fn copy_from_headers(&self, headers: &Headers) -> ErrorResult {
196        for (name, value) in headers.header_list.borrow().iter() {
197            self.Append(
198                ByteString::new(Vec::from(name.as_str())),
199                ByteString::new(Vec::from(value.as_bytes())),
200            )?;
201        }
202        Ok(())
203    }
204
205    fn append(&self, name: ByteString, value: &ByteString) -> ErrorResult {
206        // 1. Normalize value.
207        let value = trim_http_whitespace(value);
208
209        // 2. If validating (name, value) for headers returns false, then return.
210        let Some(mut valid_name) = self.validate_name_and_value(name, value)? else {
211            return Ok(());
212        };
213
214        // Validated tokens are always ASCII.
215        valid_name.make_ascii_lowercase();
216
217        // 3. If headers’s guard is "request-no-cors":
218        if self.guard.get() == Guard::RequestNoCors {
219            // 3.1. Let temporaryValue be the result of getting name from headers’s header list.
220            let tmp_value = if let Some(mut tmp_value) =
221                get_value_from_header_list(&valid_name, &self.header_list.borrow())
222            {
223                // 3.3. Otherwise, set temporaryValue to temporaryValue, followed by 0x2C 0x20, followed by value.
224                tmp_value.extend(b", ");
225                tmp_value.extend(value);
226                tmp_value
227            } else {
228                // 3.2. If temporaryValue is null, then set temporaryValue to value.
229                value.to_vec()
230            };
231            // 3.4. If (name, temporaryValue) is not a no-CORS-safelisted request-header, then return.
232            if !is_cors_safelisted_request_header(&valid_name, &tmp_value) {
233                return Ok(());
234            }
235        }
236
237        // 4. Append (name, value) to headers’s header list.
238        match (
239            HeaderName::from_str(&valid_name),
240            HeaderValue::from_bytes(value),
241        ) {
242            (Ok(name), Ok(value)) => {
243                self.header_list.borrow_mut().append(name, value);
244            },
245            _ => {
246                warn!("Could not set header \"{valid_name:?}: {value:?}\"");
247            },
248        };
249
250        // 5. If headers’s guard is "request-no-cors", then remove privileged no-CORS request-headers from headers.
251        if self.guard.get() == Guard::RequestNoCors {
252            self.remove_privileged_no_cors_request_headers();
253        }
254
255        Ok(())
256    }
257
258    /// <https://fetch.spec.whatwg.org/#concept-headers-fill>
259    pub(crate) fn fill(&self, filler: Option<&HeadersInit>) -> ErrorResult {
260        match filler {
261            Some(HeadersInit::ByteStringSequenceSequence(v)) => {
262                for seq in v {
263                    if seq.len() == 2 {
264                        self.append(seq[0].clone(), &seq[1])?;
265                    } else {
266                        return Err(Error::Type(cformat!(
267                            "Each header object must be a sequence of length 2 - found one with length {}",
268                            seq.len()
269                        )));
270                    }
271                }
272                Ok(())
273            },
274            Some(HeadersInit::ByteStringByteStringRecord(m)) => {
275                for (key, value) in m.iter() {
276                    self.append(key.clone(), value)?;
277                }
278                Ok(())
279            },
280            None => Ok(()),
281        }
282    }
283
284    pub(crate) fn for_request(cx: &mut JSContext, global: &GlobalScope) -> DomRoot<Headers> {
285        let headers_for_request = Headers::new(cx, global);
286        headers_for_request.guard.set(Guard::Request);
287        headers_for_request
288    }
289
290    pub(crate) fn for_response(cx: &mut JSContext, global: &GlobalScope) -> DomRoot<Headers> {
291        let headers_for_response = Headers::new(cx, global);
292        headers_for_response.guard.set(Guard::Response);
293        headers_for_response
294    }
295
296    pub(crate) fn set_guard(&self, new_guard: Guard) {
297        self.guard.set(new_guard)
298    }
299
300    pub(crate) fn get_guard(&self) -> Guard {
301        self.guard.get()
302    }
303
304    pub(crate) fn set_headers(&self, hyper_headers: HyperHeaders) {
305        *self.header_list.borrow_mut() = hyper_headers;
306    }
307
308    pub(crate) fn get_headers_list(&self) -> HyperHeaders {
309        self.header_list.borrow_mut().clone()
310    }
311
312    /// <https://fetch.spec.whatwg.org/#concept-header-extract-mime-type>
313    pub(crate) fn extract_mime_type(&self) -> Vec<u8> {
314        extract_mime_type(&self.header_list.borrow()).unwrap_or_default()
315    }
316
317    /// <https://fetch.spec.whatwg.org/#concept-header-list-sort-and-combine>
318    pub(crate) fn sort_and_combine(&self) -> Vec<(String, Vec<u8>)> {
319        let borrowed_header_list = self.header_list.borrow();
320        let mut header_vec = vec![];
321
322        for name in borrowed_header_list.keys() {
323            let name = name.as_str();
324            if name == "set-cookie" {
325                for value in borrowed_header_list.get_all(name).iter() {
326                    header_vec.push((name.to_owned(), value.as_bytes().to_vec()));
327                }
328            } else if let Some(value) = get_value_from_header_list(name, &borrowed_header_list) {
329                header_vec.push((name.to_owned(), value));
330            }
331        }
332
333        header_vec.sort_by(|a, b| a.0.cmp(&b.0));
334        header_vec
335    }
336
337    /// <https://fetch.spec.whatwg.org/#ref-for-privileged-no-cors-request-header-name>
338    pub(crate) fn remove_privileged_no_cors_request_headers(&self) {
339        // <https://fetch.spec.whatwg.org/#privileged-no-cors-request-header-name>
340        self.header_list.borrow_mut().remove("range");
341    }
342
343    /// <https://fetch.spec.whatwg.org/#headers-validate>
344    pub(crate) fn validate_name_and_value(
345        &self,
346        name: ByteString,
347        value: &[u8],
348    ) -> Fallible<Option<String>> {
349        // 1. If name is not a header name or value is not a header value, then throw a TypeError.
350        let valid_name = validate_name(name)?;
351        if !is_legal_header_value(value) {
352            return Err(Error::Type(c"Header value is not valid".to_owned()));
353        }
354        // 2. If headers’s guard is "immutable", then throw a TypeError.
355        if self.guard.get() == Guard::Immutable {
356            return Err(Error::Type(c"Guard is immutable".to_owned()));
357        }
358        // 3. If headers’s guard is "request" and (name, value) is a forbidden request-header, then return false.
359        if self.guard.get() == Guard::Request && is_forbidden_request_header(&valid_name, value) {
360            return Ok(None);
361        }
362        // 4. If headers’s guard is "response" and name is a forbidden response-header name, then return false.
363        if self.guard.get() == Guard::Response && is_forbidden_response_header(&valid_name) {
364            return Ok(None);
365        }
366
367        Ok(Some(valid_name))
368    }
369}
370
371impl Iterable for Headers {
372    type Key = ByteString;
373    type Value = ByteString;
374
375    fn get_iterable_length(&self, _cx: &mut JSContext) -> u32 {
376        let sorted_header_vec = self.sort_and_combine();
377        sorted_header_vec.len() as u32
378    }
379
380    fn get_value_at_index(&self, _cx: &mut JSContext, index: u32) -> ByteString {
381        let sorted_header_vec = self.sort_and_combine();
382        ByteString::new(sorted_header_vec.into_iter().nth(index as usize).unwrap().1)
383    }
384
385    fn get_key_at_index(&self, _cx: &mut JSContext, index: u32) -> ByteString {
386        let sorted_header_vec = self.sort_and_combine();
387        ByteString::new(
388            sorted_header_vec
389                .into_iter()
390                .nth(index as usize)
391                .unwrap()
392                .0
393                .into_bytes(),
394        )
395    }
396}
397
398/// This function will internally convert `name` to lowercase for matching, so explicitly converting
399/// before calling is not necessary
400///
401/// <https://fetch.spec.whatwg.org/#forbidden-request-header>
402pub(crate) fn is_forbidden_request_header(name: &str, value: &[u8]) -> bool {
403    let forbidden_header_names = [
404        "accept-charset",
405        "accept-encoding",
406        "access-control-request-headers",
407        "access-control-request-method",
408        "connection",
409        "content-length",
410        "cookie",
411        "cookie2",
412        "date",
413        "dnt",
414        "expect",
415        "host",
416        "keep-alive",
417        "origin",
418        "referer",
419        "set-cookie",
420        "te",
421        "trailer",
422        "transfer-encoding",
423        "upgrade",
424        "via",
425        // This list is defined in the fetch spec, however the draft spec for private-network-access
426        // proposes this additional forbidden name, which is currently included in WPT tests. See:
427        // https://wicg.github.io/private-network-access/#forbidden-header-names
428        "access-control-request-private-network",
429    ];
430
431    // Step 1: If name is a byte-case-insensitive match for one of (forbidden_header_names), return
432    // true
433    if forbidden_header_names
434        .into_iter()
435        .any(|header| name.eq_ignore_ascii_case(header))
436    {
437        return true;
438    }
439
440    let forbidden_header_prefixes = ["sec-", "proxy-"];
441
442    // Step 2: If name when byte-lowercased starts with `proxy-` or `sec-`, then return true.
443    if forbidden_header_prefixes
444        .into_iter()
445        .any(|prefix| starts_with_ignore_ascii_case(name, prefix))
446    {
447        return true;
448    }
449
450    let potentially_forbidden_header_names = [
451        "x-http-method",
452        "x-http-method-override",
453        "x-method-override",
454    ];
455
456    // Step 3: If name is a byte-case-insensitive match for one of (potentially_forbidden_header_names)
457    if potentially_forbidden_header_names
458        .into_iter()
459        .any(|header| name.eq_ignore_ascii_case(header))
460    {
461        // Step 3.1: Let parsedValues be the result of getting, decoding, and splitting value.
462        let parsed_values = get_decode_and_split_header_value(value.to_vec());
463
464        // Step 3.2: For each method of parsedValues: if the isomorphic encoding of method is a
465        // forbidden method, then return true.
466        return parsed_values
467            .iter()
468            .any(|s| is_forbidden_method(s.as_bytes()));
469    }
470
471    // Step 4: Return false.
472    false
473}
474
475/// <https://fetch.spec.whatwg.org/#forbidden-response-header-name>
476fn is_forbidden_response_header(name: &str) -> bool {
477    // A forbidden response-header name is a header name that is a byte-case-insensitive match for one of
478    name.eq_ignore_ascii_case("set-cookie") || name.eq_ignore_ascii_case("set-cookie2")
479}
480
481fn validate_name(name: ByteString) -> Fallible<String> {
482    if !is_field_name(&name) {
483        return Err(Error::Type(c"Name is not valid".to_owned()));
484    }
485    match String::from_utf8(name.into()) {
486        Ok(ns) => Ok(ns),
487        _ => Err(Error::Type(c"Non-UTF8 header name found".to_owned())),
488    }
489}
490
491/// <http://tools.ietf.org/html/rfc7230#section-3.2>
492fn is_field_name(name: &ByteString) -> bool {
493    is_token(name)
494}
495
496// As of December 2019, WHATWG has no formal grammar production for value;
497// https://fetch.spec.whatwg.org/#concept-header-value just says not to have
498// newlines, nulls, or leading/trailing whitespace. It even allows
499// octets that aren't a valid UTF-8 encoding, and WPT tests reflect this.
500// The HeaderValue class does not fully reflect this, so headers
501// containing bytes with values 1..31 or 127 can't be created, failing
502// WPT tests but probably not affecting anything important on the real Internet.
503/// <https://fetch.spec.whatwg.org/#concept-header-value>
504fn is_legal_header_value(value: &[u8]) -> bool {
505    let value_len = value.len();
506    if value_len == 0 {
507        return true;
508    }
509    match value[0] {
510        b' ' | b'\t' => return false,
511        _ => {},
512    };
513    match value[value_len - 1] {
514        b' ' | b'\t' => return false,
515        _ => {},
516    };
517    for &ch in value {
518        match ch {
519            b'\0' | b'\n' | b'\r' => return false,
520            _ => {},
521        }
522    }
523    true
524    // If accepting non-UTF8 header values causes breakage,
525    // removing the above "true" and uncommenting the below code
526    // would ameliorate it while still accepting most reasonable headers:
527    // match str::from_utf8(value) {
528    //    Ok(_) => true,
529    //    Err(_) => {
530    //        warn!(
531    //            "Rejecting spec-legal but non-UTF8 header value: {:?}",
532    //            value
533    //        );
534    //        false
535    //    },
536    // }
537}
538
539/// <https://tools.ietf.org/html/rfc5234#appendix-B.1>
540pub(crate) fn is_vchar(x: u8) -> bool {
541    matches!(x, 0x21..=0x7E)
542}
543
544/// <http://tools.ietf.org/html/rfc7230#section-3.2.6>
545pub(crate) fn is_obs_text(x: u8) -> bool {
546    matches!(x, 0x80..=0xFF)
547}
script/dom/fetch/headers.rs

script/dom/fetch/
headers.rs
